Azure CosmosDb Autoscale billed for max RU per hour not adding up to RU utilization

user_559341 0
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For the Month of September our Cosmos bill was $878.41. We have one write region in west EU and one readonly in north EU. We are set to 10,000 RU Autoscale. When I check the azure calculator with that configuration, its showing that a 100% utilization would cost $1752 a month. Our bill for the month was $878.41 which would make sense if we were running at 50% utilization but we are not.

Based on the Normalized RU Consumption Metric, we are running at 89% average over 7 days or 100% MAX per hour for the whole month. Shouldn't we be billed for the max RU consumption we hit per hour, which in our case is 100% or 10,000 RU, making our bill $1752?

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5 minute time slice last 7 days (Normalized RU Consumption metric) enter image description here

azure-billing azure-cosmosdb
1 Answers

You need to look at the provisioned throughput metric.

NormalizedRUConsumption is the Max RU consumption percentage for any partition in any second.

With Autoscale you are charged for the max provisioned throughput reached in any hour.

However the provisioned throughput won't automatically be raised to the auutoscale max if a single partition spikes to 100% in a single second.

The provisioned throughput is raised if you exceed current provisioned throughput averaged over a 5 second period (I was told this by support when I questioned something similar).

user_732260
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